A 140 foot by 140 foot paved area is to be sloped for drainage at 1/8 inch per foot. What is the elevation at the edge of the pavement if the center point elevation is 87.2 feet?

To determine the elevation at the edge of a 140-foot by 140-foot paved area that is sloped for drainage at a rate of 1/8 inch per foot, we need to first calculate how much the elevation changes from the center to the edge.

The center point elevation is given as 87.2 feet. The slope is 1/8 inch per foot, which we need to convert into feet for our calculations. Since there are 12 inches in a foot, 1/8 inch is equivalent to 1/8 ÷ 12 = 1/96 feet per foot of slope.

Next, we calculate the distance from the center of the paved area to the edge. Since the area is square and measures 140 feet by 140 feet, the distance from the center to one edge is half of the side length, which would be 70 feet.

Now, we can calculate the total change in elevation over this distance due to the slope:

Change in elevation = slope rate × distance = (1/96 feet/foot) × 70 feet = (70/96) feet = 0.7292 feet (approximately).

To find the elevation at the edge, we subtract this change in elevation